It is well known to apply vacuum under air-tight wound covers in treating wounds. The vacuum can be used to suction wound exudate and other liquids from the wound and wound packing materials, and can be applied as a healing modality for its well known antiseptic and tissue regeneration effects.
The earliest devices for vacuum assisted wound therapy merely ran a tube, such as a Jackson Pratt hemovac drain or other similar tube with a ported distal end, under the edge of wound cover and applied an adhesive or paste around tube to maintain the air-tight seal. The other end of the tube was connectable to a pressure regulator of a hospital vacuum system, and sufficient negative pressure was applied to drain the wound and assist in healing. These devices reduced the frequency of dressing changes and the risk of infection as compared to conventional dressings. See, e.g., M. E. Chariker, et al, “Effective Management of Incisional and Cutaneous Fistulae with Closed Suction Wound Drainage”, Contemporary Surgery, vol. 34, June 1989, pages 59-63. Other similar devices connected the end of a vacuum suction tube into a foam pad or other wound packing, and used a separate fluid supply tube for introducing medications or flushing fluid into the pad or wound packing. See, e.g. U.S. Pat. No. 4,382,441 (Svedman).
The adhesive seal around the vacuum tube or tubes which run under the edge of the wound cover in these prior wound dressings is vulnerable to cracking and breaching the air-tight seal created by the cover. Devices with more durable vacuum tube connections include using a tube with a flared or flanged distal end that can be fixed directly to the wound cover over a hole punched into the cover, as shown in U.S. Pat. No. 3,367,332 (Groves). U.S. Pat. No. 6,071,267 (Zamierowski) discloses a combination of these prior art devices in which a medication supply tube runs under the edge of the primary cover and a vacuum tube is connected into a foam pad located over a hole in the primary cover. U.S. Pat. No. 6,345,623 (Heaton) discloses another approach in which a suction head having a vacuum tube connector is placed on a foam pad in the wound, then a surgical drape with a hole in its center is placed over the suction head such that the connector protrudes up through the hole.
In their efforts to improve over these prior art devices, the present inventors considered several design objectives; including the objective of providing greater integrity to the seal between the primary wound cover and the skin, and determined that it would be preferable to locate the tube attachment on the outside of the primary wound cover rather than running the tube or tubes under the edge of the cover or through a slot or a seam in the cover. In addition to providing a more secure seal, locating the tube attachment on the outside of the primary wound cover allows the wound packing materials to be optimized to promote tissue growth and wound healing, since the packing materials do not need to provide support or connection for the tubes.
Locating the vacuum tube attachment on the outside of the primary wound cover can be accomplished by a tube that is integrally attached to the primary cover and that has a sidewall port located over a hole in the primary cover, as shown in published application US 20040064132. However, another design consideration for the present invention was that it would be an advantage over prior vacuum dressings to provide the tube attachment in the form of a patch that can be applied to a primary wound cover, rather than as an integral part of the outer surface of the cover. This feature allows the same patch to be used with primary wound dressing covers of different sizes and shapes, and allows the caregiver to locate the patch in the most convenient location over the wound, as opposed to using an integral device in which the tube is attached over a hole at a fixed location on the primary cover. As an additional advantage, the same patch can be detached and reused on a new primary cover when the dressing is changed, and in the rare event of a patch needing to be replaced, it can be replaced without removing the primary cover from the wound.
In the course of developing a vacuum assisted wound system using a tube attachment patch, the inventors discovered that the patch can be used by itself to provide a vacuum applicator over small wounds. Although not a primary objective, this alternative use should be considered an additional aspect of the invention.
These and other advantages and aspects of the invention will become apparent upon reading the detailed description and drawings which follow.